You Can't Do That on Television

A CanadianTV show that aired on Nickelodeon in the United States starting in the late 1980s. Each episode had a theme and consisted of a series of loosely connected skits performed by teenage actors that describe a comical aspect of that theme. They had a ridiculous segment where the cast would sit around an chat, until someone said the forbidden phrase "I don't know", and green slime would fall onto their head from the ceiling.